A large amount of software in the DoD is embedded into weapon systems. Missiles, aircraft, tanks, and command and control systems all rely nearly completely upon software for correct mission fulfillment. Often the software process for these types of systems is poorly defined and is implemented by a small group of people. Also, embedded systems are commonly written in assembly language and are comparatively small. The systems have existed for many years yet may be poorly documented and engineered. In many circumstances, this software may be most critical to the national defense and requires quick and accurate upgrades to be most effective.